The attack is raising fears that Syria's civil war is increasingly spreading into Lebanon, where the Shiite Hezbollah group is backing Syrian President Bashar Assad.

The rocket that hit Hussein's house in Chiyah on Sunday morning came minutes after another landed at a car dealership about a mile away in Mar Mikhael. Four Syrian workers were injured at the dealership, according to the state-run National News Agency. Ten cars were also damaged.

Lebanese media said security forces were searching for a third unexploded rocket.

The attacks occurred the morning after Hezbollah's leader, Sayyed Hassan Nasrallah, admitted clearly for the first time that his group had been fighting in Syria for several months.

"We are going to continue down this road and take responsibility. We accept all the sacrifices ... that come with this responsibility," he said in a televised speech Saturday night. "I promise you victory."

Abu Ali Qbeisi, the owner of the car dealership, told a local TV station that he believed the rockets were a Syrian rebel response to Nasrallah's speech.

"We will not be frightened," he said, according to Lebanon's Daily Star newspaper. "Long live Nasrallah."

In a video published online earlier this week, a threat to strike the area of south Beirut was made by Col. Abdul-Jabbar al-Aqidi, commander of the Syrian rebels' military council in Aleppo.

"We used to say before, 'We are coming Bashar.' Now we say, 'We are coming Bashar and we are coming Hassan Nasrallah,' " he said. "We will strike at your strongholds in Dahiyeh, God willing."

Syria's main opposition group, the Syrian National Council, slammed Nasrallah's speech as an "an attempt to pit the Lebanese people against their Syrian brothers and sisters who have revolted against the brutal dictator."

In a statement Sunday, it said his speech "has the potential for serious ramifications in the region."

"It explicitly declares Iranian interests as superior to the basic, inherent rights of people across the region," the statement said.

The attacks come in the midst of heavy fighting in the city of Tripoli. Those clashes have continued for a week as Sunni and Shiite gunmen fire mortars, grenades and machine guns at each other. At least 25 have been killed.

Meanwhile, Syrian rebels are under attack in Qusair, a strategic rebel-held town on the Syria-Lebanon border. Shiite fighters and Syrian government forces began the offensive last week in an attempt to drive the rebels out of the important supply route.

Lebanon is struggling to keep out of the violence in Syria, which in the past two years has claimed some 80,000 lives, according to the U.N. Hezbollah fighters as well as Sunni rebels are using Lebanon as a gateway to Syria while nearly half a million refugees from Syria seek aid in Lebanon.